Wind power rules, small wind pwr, not so much...

[bigmoose]

Folks,

I have always had a penchant for alternate energy since the early 70's. It may not show at times, because it has always been tempered by the "business case", that is it has to not only work out with respect to energy balance; but economically also.

Here is an article that makes a fair analysis on wind power turbine capability versus size:
http://www.theoildrum.com/node/6954

Two real-world tests performed in the Netherlands and in the UK confirm our earlier analysis that small wind turbines are a fundamentally flawed technology. Their financial payback time is much longer than their life expectancy, and in urban areas, some poorly placed wind turbines will not even deliver as much energy as needed to operate them (let alone energy needed to produce them). Given their long payback period relative to their life expectancy, most small wind turbines are net energy consumers rather than net energy producers.

12 turbines were tested in the Netherlands with data provided. It took two to 47 small windmills to power a Dutch home... and an American home consumes 3X the power!

Size matters
...snip...a large wind turbine with a rotor diameter of 18 meters delivers 143,000 kWh per year, or an average power output of 16,324 watts. It can power 42 Dutch households. This large wind turbine costs only slightly more than all small wind turbines combined (17 percent more, to be exact, or 190,000 euro), but it delivers almost 20 times as much energy.

Very interesting facts... Cost 17% more; power 2000 % more. What a deal! I'll let you read the original article so that I don't quote too much.

The discussion gets pretty good also. The pro and con. Here is a graph, if it turns out that I thought was pretty interesting that I have not seen before. Manufacturer spec for output versus wind speed, versus measured performance.

Why my interest? I was involved with a few Gents two years ago who wanted to import small vertical axis German wind turbines into the USA. They were friends, and were not happy when I told them they were "nuts" and the economics won't work out for their customers. I shared with them that they might make a profitable business out of it; but I didn't want to be a part of it, because there would be no real ROI (Return on Investment) for their customers. We have stayed friends, and they did not initiate an investment to become involved...

I am still looking for the right "small" solution...

 

[jag]

Large compared to smalll wind turbines.

Very interesting facts... Cost 17% more; power 2000 % more.

Yup, most deployments of wind power by utilites I've seen are 18m and up turbine diametre. Where my father and uncle lives on the Swedish west coast there are already several wind farms with comparably large turbines in groups of 5-10.

That doesn't mean there is not a business case for small. Rural homes could use wind turbines sized for a household to replace or supplement a diesel generator. Sailors already use very small ones to charge on-board batteries while moored on bouys.

 

[John in CR]

Thanks for the info BigMoose. It supports my thinking that wind or dish stirling solutions make more sense if done as a neighborhood power solution. The flipside though is that DIY wind turbines can be done very cheaply. Even then you have to look at it as part of a hobby instead of just a dollars and cents economic return. In those terms, there's gotta be a lot of value in the satisfaction of generating your own energy, and from an economic perspective then you have to also consider the money that you'd spend doing something else with your free time. Plus getting your kids involved and having them learn how it can be done is a priceless benefit.

Last, how do you put a dollar value on "sticking it to the man"? The man in this case is the utilities company. How do you put a value on having power when the power goes out for everyone else? How do you put a price on the insurance it represents against future price increases, or the remote chance of the shit really hitting the fan in your region of the world leaving most without power for an extended period.

The bottom line is that I don't think it's a fair and complete comparison to look at the cost of your alternative energy item against only the present value of the electricity that you'd otherwise have to buy from the utilities company.

Of course the big economic return that everyone can take advantage of is in conservation, but that's just not as sexy as having some kind of structure. It's like something everyone knows, but doesn't want to talk about, though that sentiment does show signs of changing this past year, hopefully not just until the recession is over. Luke mentioned you have some really interesting passive systems in place. Care to share any of the things you've done?

John

 

[veloman]

This makes sense to me, based of how energy expenditure increases expotentially with speed and the whole economies of scale factor.

If I try making my own turbine, I will have to shoot for a pretty large span. Might as well do it right, a 20 foot wide turbine wouldn't be a ton more work than a 5 foot wide one.

However, I am interested in vertical axis turbines, they spin great no matter the wind direction. And from the looks of it, should have a lower start up speed, less support structure.

 

[MitchJi]

Hi,

Here is a graph, if it turns out that I thought was pretty interesting that I have not seen before. Manufacturer spec for output versus wind speed, versus measured performance.

It looks exactly like EV manufacturer spec for range vs actual range :lol:

 

[Evoforce]

I think my neighbors would complain if I put up a big bertha.

 

[dogman dan]

A lot depends on how you calculate the math on cost effectiveness. Once you already have the solar equipment in place, adding a small wind generator can make sense. The cost is cut at least in half by already having the inverter, grid tie, etc.

However, as with all wind power, it has to be installed in a place that makes some sense. A few trees in the nieghbors yard is all it takes and now you are screwd. Few houses on less than an acre or two of lot will have the space to put up a tower tall enough, which brings you back to too expensive. If you live in the praries on a farm or a breezy beach where you get good wind, then it's different, and you can use a cheap short tower.

They may be gone now, but you used to be able to drive by a display of the history of wind generators driving from Palm Springs to LA. At a glance, you could see how location was everything for wind towers, and how the short towers were worthless compared to the tall ones. We balloonists are very aware of how the land screws up the wind for at least the first 200 feet up. Above 200 feet, much faster, and much less turbulence in the breeze.

 

[joe tomten]

in the "small" category they don't differentiate between what I consider to be "toys" and 10kw machines truely engineered to stand up to the rigors of wind power production - for a long time.

Toys are a couple hundred watts peak output achieved at 13 m/sec (say 28mph).

Just because some company makes a some sexy looking "product" for $600 that they can convince people to put on a pole somewhere below the tree line - doesn't mean that that product will ever pay for itself.

where i live, if i were to add a low power (1kWpeak) direct drive low rpm machine with an approx 3.5m (10') blade diameter turbine on a guyed pole tower at 50m (150') off the ground - and connect it to the current balance of solar system that I have in place (only 1kw peak) it would be a result in a substantial reduction in my use of grid power.

Re: vertical axis turbines.
They are toys. These are sold to people who don't understand or care how to ever get a return on their investment.
Entities who make a living selling wind power, and those designing and manufacturing turbines to be used, where economics matter, learned this decades ago. It doesn't make sense to install a wind generator where there is significant turbulance, because it is near impossible to collect useful energy (achieve lift) out of turbulant air.

"edit"
I actually read the article: the turbines tested were all toys. a couple of exceptions, maybe

 

[commanda]

I have 2 acres out in the country, where I'm about to build shortly. There is utility company power on the other side of the road. They quoted me $20,000 to connect power, so they can then have the priviledge of sending me a bill every quarter.
$20K buys a lot of solar, batteries, and wind turbines.

Replacing already connected utility power with wind & solar doesn't make economic sense. On a greenfield site, where cost of connecting utility power is expensive, it then makes sense.

Amanda

 

[spinningmagnets]

Commanda, do some research over at builditsolar.com, and also at otherpower.com, I believe they can save you a lot of "re-inventing the wheel". (edit: PS, I apologize if you already know all this)

http://www.builditsolar.com/
http://www.otherpower.com/
http://www.thebackshed.com/

A couple of years ago, I spent all my free time researching and developing a plan for my retirement. It involved paying cash for a remote property within driving distance of a fair-sized city (for supplies). I like VAWTs, and they are useful for pumping water, but not generating a useful amount of electricity. For water-pumping VAWTs, I like a 3 drum Savonius and a double stacked Lenz, both easy to make.

http://catapultdesign.org/wpcatapult/wp-content/uploads/2009/10/Savonius-Lenz-Turbines.jpg
http://www.windstuffnow.com/main/Lenz_Turbine_diagram2.JPG
http://www.linux-host.org/energy/savonius_turbine.jpg

For electricity, FIRST, check if you are ALLOWED to have one on your property. Then, build a pole tower at your most-desired site. Make a small anemometer (wireless bike speedometer and cups) and starting at a height of 30', data log the wind at your site. Raise the anemometer 5", and repeat, repeat, etc. Set the pole top as high as humanly possible (higher than you would mount a wind-gen). Once you know how much wind you have at that particular spot (at the different levels) then...you can begin to plan.

The sweet-spot for a DIY wind-gen seems to be a 17' diameter disc (three 8' blades). If you build a wind-gen that is 22', the amount of loading the tower will feel in high winds (even with the turbine furled) will significantly increase the strengthening and cost of the tower. Also remember you must lower and perform maintenance on the turbine at regular intervals. Two 17-footers 'might' be better than a single 22'.

Alternative energy for society is one discussion, AE for an individual is a completely different ball game. I have no hands-on experience with AE, but I will share my research and the resulting options with anyone who is interested. I can provide a short index list of what I consider the best avenues of effort for your consideration, or, many pages of my conclusions...

 

[MitchJi]

Hi,

I am still looking for the right "small" solution...

This should be small enough and cheap enough :
http://peswiki.com/index.php/Directory:Humdinger_Windbelt

The Windbelt utilizes the aeroelastic effect seen when a ribbon, stretched between two fasteners, vibrates in the wind. It is the first turbine-less design, and is targeted for capturing wind energy on the sub-100-Watt scale. Rotation-based wind turbines don’t scale down well due to friction and the lower energy of lower wind speeds.

Invented by Shawn Frayne, the Windbelt is a taut membrane fitted with a pair of magnets that oscillate between coils. Designed for low wind speeds and budgets, the device is 10x to 30x times more efficient than the best microturbines, and its cost is proportionately small. Frayne envisions Windbelts being made available for $2 - $5.00, able to provide electricity for small lights and radios in the third world.

The technology is still in its infant stages and will need quite a bit more R&D before it is ready for commercial roll-out.

One of these might fit where there isn't enough space for a larger conventional wind turbine:
http://www.alternative-energy-news.info/flodesign-wind-turbine-business/

The company was founded in 2007, after leveraging its knowledge of turbine design based on the jet engine technology. Its shrouded wind turbine design is expected to deliver more than three times the amount of energy as traditional wind turbines for the same size rotor. The rotors of its turbines are very small in size and they can be easily installed and utilized at places where there is high consumption of power but there is no space for conventional wind turbine towers; airports, for instance. It’s significantly smaller compared to other wind turbines and also costs a lot less to install and operate. With the help from MassCEC’s Renewable Energy Trust the Massachusetts Port Authority has already shown a keep interest in deploying FloDesign’s wind turbine technology.

[youtube]j8Si-74IcrQ[/youtube]

Two affordable Solar methods:

How To Build a Solar Generator
Now two groups at MIT are working on alternative approaches to solar-based electricity that could significantly cut costs -- and put the ability to harvest electricity from the sun into the hands of villagers in poor countries and backyard tinkerers alike.

http://www.technologyreview.com/read_article.aspx?id=17169&ch=biztech&pg=1

During a stint in the Peace Corps in Lesotho in southern Africa, Matthew Orosz, an MIT graduate student advised by Harold Hemond, professor of civil and environmental engineering, learned that reflective parabolic troughs can bake bread. Now he plans to use these same contraptions to bring power to parts of Africa baked in sun but starved for electricity. His solar generators, cobbled together from auto parts and plumbing supplies, can easily be built in a backyard.

The basic design of Orosz's solar generator system is simple: a parabolic trough (taking up 15 square meters in this case) focuses light on a pipe containing motor oil. The oil circulates through a heat exchanger, turning a refrigerant into steam, which drives a turbine that, in turn, drives a generator.

The refrigerant is then cooled in two stages. The first stage recovers heat to make hot water or, in one design, to power an absorption process chiller, like the propane-powered refrigerators in RVs. The solar-generated heat would replace or augment the propane flame used in these devices. The second stage cools the refrigerant further, which improves the efficiency of the system, Orosz says. This stage will probably use cool groundwater pumped to the surface using power from the generator. The water can then be stored in a reservoir for drinking water.

The design uses readily available parts and tools. For example, both the feed pump and steam turbine are actually power-steering pumps used in cars and trucks. To generate electricity, the team uses an alternator, which is not as efficient as an ordinary generator, but comes already designed to charge a battery, which reduces some of the complexity of the system. And, like power-steering pumps, alternators, including less-expensive reconditioned ones, are easy to come by.

As a result, the complete system for generating one kilowatt of electricity and 10 kilowatts of heat, including a battery for storing the power generated, can be built for a couple thousand dollars, Orosz says, which is less than half the cost of one kilowatt of photovoltaic panels.

"You can't afford something that's designed for solar. You have to buy something that's mass-produced for something else -- that way the cost is reasonable," says Duane Johnson, owner of Red Rock Energy, in White Bear Lake, MN, who developed and sells thousands of the inexpensive LED-based sun-tracking devices Orosz uses to orient the solar concentrators. Most of the devices are used to position photovoltaic panels, he says, but some people are using them with old satellite dishes to concentrate heat and make steam. Sales of his devices have been growing 25 percent a year, a rate similar to that of the solar photovoltaics industry.

Having already built a working prototype, Orosz's next step, which he hopes to accomplish starting this September in Lesotho, is to optimize manufacturing and set up a financing system, drawing on a recent $100,000 World Bank grant, to make the system affordable to villagers who would likely use the generator in a community center and as a battery-charging station.

Although their system was originally designed for Lesotho, Orosz and his colleagues believe it might appeal to amateurs elsewhere. "Backyard tinkerers could build it themselves. No doubt about it," says Amy Mueller, an MIT graduate student who's taken on a leading role in Orosz's project. "Matt's dad has one of these that we built to heat his Jacuzzi."

http://www.technologyreview.com/read_article.aspx?id=17169&ch=biztech&pg=2

Repurposed auto parts aren't the only way to go. Amy Sun, a graduate student in MIT's Media Lab, has designed an inexpensive system that uses heat from a solar concentrator to drive a type of turbine originally patented by Nicola Tesla. Rather than making complex, difficult-to-manufacture bladed turbines, Sun turned to the Tesla turbine, which consists of simpler flat disks stacked like records on a central shaft. The disks are carefully spaced to allow steam to flow between them. As the steam flows, friction between the steam and the surface of the disks causes them to rotate. "Once I have rotational shaft work, I can couple it to almost anything -- an air pump, compressor, fan, mixer, grinder, sewing machine, refrigeration compressor, and, to power those very few things that are truly electric in nature, an electric generator." She calculates that this system, which she says is simple enough for an eight-year old to make, can produce cheap power.

Of course the overall economics of these solar generator systems depend on how long they will last and how much maintenance they will require. The lifetime for Orosz's system could be quite good, since it uses parts designed for rugged service in vehicles. It also works at relatively low temperatures that, in addition to making it safer and easier to work with, won't strain the performance limits of the plumbing used.

More info on the Orosz's solar generator system here:
http://planetgreen.discovery.com/tech-transport/green-inventors-solar-microgenerator.html

 

[John in CR]

Too bad they haven't come up with a practical flying wind generator on a tether, because unless you have some very unique location on a mountain, a home sized wind generator simply can't be high enough like Dogman said, because the towers are where all the cost is. Magenn's spinning blimp doesn't fall into the practical category. I'm sure an airfoil can fly plenty of wind generator cheaply, but it's automating the landing and take-offs that's the real issue.

Mitch,

The wind belt obviously isn't ready. It's been a few years and haven't heard anything more, so probably a dead end.

I looked at the MIT project in Lesotho 4 or 5 years ago, and came up short on details, but the fact that the prototypes aren't still in operation shows the fragility of the system. Rankine cycle engines require plenty of maintenance, and that's what always gets me back to the stirling cycle free piston engines. I just need to do a vulcan mind meld with BigMoose to be able to build a good one.

That Flow Design turbine is interesting. I wonder if it's real. When they make mistakes like saying a typical turbine only captures half of the energy, and then later say their turbine is 3-4 times better, it throws up a big fat red flag for me. Plus if that cowling creates and focuses a spinning airflow like that, why isn't there a turbine at that focal point???

John

 

[commanda]

Commanda, do some research over at builditsolar.com, and also at otherpower.com, I believe they can save you a lot of "re-inventing the wheel".

http://www.builditsolar.com/
http://www.otherpower.com/
http://www.thebackshed.com/

I have been a long time member of otherpower (I use the same handle over there). If memory serves me correctly, it may have been I who pointed you at ES.
And one of my standing philosophies, I never re-invent the wheel. And my accumulating AHr meter started from Glen's Picaxe logger (thebackshed).

Amanda

 

[MitchJi]

Hi John,

Too bad they haven't come up with a practical flying wind generator on a tether, because unless you have some very unique location on a mountain, a home sized wind generator simply can't be high enough like Dogman said, because the towers are where all the cost is. Magenn's spinning blimp doesn't fall into the practical category. I'm sure an airfoil can fly plenty of wind generator cheaply, but it's automating the landing and take-offs that's the real issue.

Maybe Makani Power has but its not DIY or home scale:
http://www.makanipower.com/

Makani Power is developing Airborne Wind Turbines (AWT) to extract energy from powerful, consistent winds at altitude. Makani AWTs will produce energy at an unsubsidized real cost competitive with coal-fired power plants, the current benchmark of the lowest cost source of power.

This website highlights the rigorous small-scale testing program Makani has undertaken to demonstrate core functionality and validate performance expectations for the M1, Makani’s first utility-scale 1 MW system.

http://www.makanipower.com/concept/makani-m1/
http://www.makanipower.com/concept/fundamentals/

 

[bigmoose]

John,

I'll try to help with what I can. From my old day job, we looked at any and every cycle for energy conversion in the hundred watt to 5 kw area. We had Brayton ceramic turbines the size of a dime spinning at a few hundred thousand rpms, organic rankine cycles, photo voltaics (PV), thermo photo voltaics (TPV), and of course Stirling.

After years of trade studies and laboratory tests we settled on a free piston Stirling design from this company:
http://www.sunpower.com/lib/sitefiles/pdf/productlit/Engine%20Brochure.pdf

Note they publish an achieved efficiency of 36%. I can attest that that is real. It is BTU in to electricity out of a linear alternator. We measured consistently more in tests of our "made to order" Stirling convertor. It also is cost prohibitive for any commercial use. It works and works well. Guaranteed life of around 20 years.

Here is their 1KW unit running on sawdust pellets:
http://www.ohio.edu/mechanical/thermo/Intro/Chapt.1_6/StirlCogen/StirlCogen.html

Here is a 7kw design paper from the same firm:
http://pointfocus.com/images/pdfs/7kwstirling.pdf

Here is a nice Power Point from a prof at Auburn University. This gent used to be a principal in the development 12 or so years ago, retired from Aerospace to Auburn.
http://sri.auburn.edu/papers/2008/stirling_convertors_for_military_and_space.pdf

Another manufacturer I am familiar with has a sun concentrator Stirling cycle
http://thepowerdish.com/technology.html

The clearances in all these high efficiency machines are quite tight. No one is going to be capable of building machines of this class in their basement. Assembly is an art form, and a credit to the technicians that do it on a daily basis. Once hermetically sealed, the unit is quite robust.

Perhaps that will help John!

 

[John in CR]

Mitch,
Nice find on that Makani Power wind wing generator. Anyone who has flown stunt kites can really appreciate that concept, though I don't know why they fly it in a circle. I think a shallow figure 8 would be better and eliminate the cable twist problem.

BigMoose,
I can understand that a stirling designed for space use would be cost prohibitive for commercial use. BTW, other than the heat source, what drove the cost? Some unobtainium material for the regenerator? My big question is if quite efficient stirling engines are already in commercial use as coolers in soda vending machines and even Coleman coolers, why cann't we already buy 3-5kw or even 10-12kw solar dish stirling power generators?

At some point I'm going to have to talk with you about my super simple closed cycle high compression engine design that has 2 one way valves and the only other moving part is the piston. Other than the simplicity, the beautiful part is that it includes a real regenerator, not a recuperator. What it lacks in efficiency I think is made in simplicity. I just lack the mechanical knowledge to figure out how to do the valves.

John

 

[spinningmagnets]

Anyone who is serious about building a Stirling quickly comes to realize they will be physically big for a small power output. I agree with bigmoose that I can't imagine me trying to build a free-piston unit with linear alternator in a garage, but...

Consider making a copy of the "Jim Dandy #5", a vertical twin Gamma with a double-acting power cylinder...http://www.starspin.com/stirlings/pictures.html

If you must build a stirling in your garage, also consider a copy of the Rider-Alpha, I seem to remember over 3,000 being built just before electricity became widely available (for pumping water). Its a vertical 2-cylinder, crank on top, the cylinders and pistons can be made from pipe...Garage 'do-able'. The detailed Rider-Alpha patents are listed (in plain english) in the files section of the Hot-Air-Engine-Society (HAES), under 'Ron Roberts stuff' (sorry, you must also join that forum to view files), HAES link in the index below.

http://www.oldengine.org/members/orrin/lnk_stir.htm

 

[John in CR]

If simple coffee cup free piston stirling can work and such a low temperature differential, then one that produces power can be done at home, as long as you don't expect to get high efficiency. There are just some very tricky design factors that you have to get right, and in the end it needs to operate at the correct harmonic resonance under load. At one point Sunpower shared some technical papers that contained what seemed to be the detailed math needed to figure it out. I tried doing one with a speaker motor as my linear alternator using the sun as my heat source, but I finally determined that the surround and spider were too well damped to sustain operation. I never could figure out how to make a proper planar spring. I was really pleased with my solar collector that was giving me a delta T of well over 100° without concentration. The idea was to build an army of miniature engines made with cheap mass produced speaker parts, with specially wound low resistance coils, to cover a roof, all tuned to the same 60hz frequency. Then run each row out of phase mechanically so all the noise from vibration would cancel out. Once sufficient temperature was reached in the morning or after clouds, a little amplifier would jump start all the motors using a short 60hz test tone. In the meantime solar PV became cheap enough to just drop the idea.

In 16 years of school I don't think I learned as much as I did in the year I was into hot air engines. After seeing an LTD stirling engine working off of the heat from the palm of a hand I was completely hooked. Even though I never built a useful engine it was a fun year. Ebikes were next...not as fascinating, but a whole lot more fun and tangible results are easy.

John

 

[jmygann]

Real-world tests of small wind turbines in Netherlands and the UK

http://www.theoildrum.com/node/6954

 

[MitchJi]

Hi John,

Another tethered Kite (Kitegen). They've built at least one:
http://www.kitegen.com/en/?page_id=48

A 3 MW Kite Gen Stem generator

In the “Stem” configuration the wings pull the cables that, through a pulley system, activate the alternators on ground, that produce electricity. When cables are entirely unwound, the wing is guided to a position where it looses its wind resistance and the cables are wound in. Energy consumption of the winding phase is a minor fraction of the energy generated during the unwinding phase.

At the very core of the project is the software that autonomously pilots the power kites, so that the flight patterns can be controlled and normally directed to maximise the production of energy

In 2006 Kite Gen Research has built a first prototype, codename KSU1, tested at an altitude of 800m with the authorization of ENAC and ENAV (Italian Civil Aviation Authorities).

Beyond the verification of the theoretical data, the KSU has produced energy, thanks to the unwind/rewind cycle: 5kW average and 30kW peak, with a ground of 4.5 m/s.

Stem configuration has been producing today and functioning of the first generator, near Asti – a place where wind conditions are considered to be definitely inadequate to traditional wind generators – is foreseen for the beginning of 2010.

The following video shows how the Stem generator works:
[youtube]Zl_tqnsN_Tc[/youtube]

Plans for off-shore Stem generators:
http://www.kitegen.com/en/?page_id=52

Kite Gen Stem Off-shore

At deep sea, wind availability is generally higher, both in terms of speed and hours, in comparison with ground or coastal areas. This notwithstanding, the installation of windmills on board floating platforms for deep offshore energy conversion is a difficult task because of the high thrust and moment generated by the windmill on the platform during operations.

Solutions to exploit deep offshore wind energy have been proposed by several competitors. Nevertheless, because of the enormous technical difficulties, it seems there is only a few (and costly) existing prototypes.

Kite Gen overcomes this inherent problem: the position of the centre of mass of the generator is really close to the platform deck and the direction of the main loads (represented by the mechanical pull acting on the cables), practically passing through the centre of mass of the generator, greatly reduce the infrastructure costs.
The Kite Gen take-off tower can in fact be extremely slender and light and can be oriented and lowered after the rare take-off and landing procedures, limited to the first start-up of the plant, to the periodical maintenance of the system and to extreme weather conditions. Both floating and mooring systems may be many times lighter than in other traditional wind generator: like a Ju-do wrestler Kite Gen uses the wind’s strength for energy production, while traditional windmills only arm wrestle with it.

They also have a Carousel Design:
http://www.kitegen.com/en/?page_id=96

Kite Gen Carousel

he configuration combines a series of Kite Gen generators, considered as a “base” module, where the tension in the cables is maintained constant and their length changes only to grant the wings control, in order to obtain the optimal trajectories for energy generation.

As the power kites circle in the air, at an altitude of 800 – 1000m, the vertical rotating axis of the structure activates large scale alternators, that have been geared down to receive the force exerted on them. At its full capacity the flight of the entire power kites array is guided, so as to turn the carousel at the desired speed, with a capacity factor estimated at 5,000 hours per year.

Maximum reachable size is under study, but first evaluations shows that 1,000 MW (1GW) can be exceeded, without significant structural risks, with a diameter of approximately 1,600m.

As well as the Kite Gen onshore generator, the Carousel generator finds an ideal application on off-shore platforms. The machine indeed doesn’t have thrust moments and requires minor mooring systems, while the huge available sea spaces represent an ideal solution for the generator positioning.

Kite Gen Carousel Off-shore generators represent the last step of the actual KGR work program for the implementation of the Kite Gen project.

Video of the first Kite Gen Stem unit being tested in 2006:
[youtube]QlSHH_djn94[/youtube]

 

[John in CR]

The Kite Gen is cool too. If a big one goes operational, the big question will be what daredevil hops aboard for a ride and then parachutes down? 8)

 

[veloman]

This got me thinking, how much a system would it take to generate about 200watts of wind power? Think ultra portable wind power - something you could pack up and carry with you on the bike, then set up in a few minutes wherever you stop.

Assumptions: 10mph wind, 200watt average power

Maybe use an RC outrunner with extensive reduction as the generator?


I thought of this because I'd like to travel to the beach, 22 miles away. There is great sustained wind there. But even here at my house, where there are a fair amount of trees (with some open yard), there's usually a 10mph wind. Would this idea be more practical than 200w of solar panel?

 

[jmygann]

vertical axis wind turbines

http://www.youtube.com/watch?v=aNT5XMQqCEI&feature=player_embedded

http://www.wildnaturesolutions.com/windturbines.html

 

[PedalingBiped]

I read a very inspirational book about a boy in Malwi that made a windmill with a bicycle wheel and a generator.
He invented his own switches and circuit breaker. ( a ball point pen spring held in suspension between the magnetic field of the 2 wires.)
It called "The boy who harnessed the wind"

http://williamkamkwamba.typepad.com/williamkamkwamba/photos.html

I tend to agree with Moose about the return of money with business plans.
But, there is plenty of room for DIY's.

 

[John in CR]

jmygann,

How much do those VAWTs in the pic put out in terms of power? A monthly or annual estimated number doesn't quite cut it. Let's see actual power out at various wind speeds.